Beverage service on an aircraft is usually accomplished by attendants who wheel beverage carts down the aisles of the plane, providing drinks to those passengers that request them. The challenge with most beverage carts used in today's aircraft is that these units are quite heavy and mobile, and in the event of turbulence or other aircraft movement these units can shift or even begin moving if not properly constrained, leading to a danger risk. Also, storing these carts when not in use requires that they be securely stationed, but easily and quickly released when needed. Accordingly, these carts are provided with immobilization systems that attempt to keep the beverage carts stationary when not in use but is easily disengaged when the cart needs to be released for serving the passengers.
In order to retain a catering cart within a commercial aircraft during normal service and in emergency conditions, carts are normally equipped with retraining devices commonly known as “turn buttons” that are deployed to secure the carts in place. The turn buttons are levers or handles that are rotated downward, causing the cart to engage with a lower surface of a work deck beam. However, turn buttons have inherent drawbacks in their design.
One disadvantage concerns the current trend towards the “air over” method of cart chilling that requires the cart bays to have doors. This means that the turn buttons have to be placed either on the outside of the doors or inside the doors. If placed outside the doors, there is a resultant increase in the depth of the galley when the carts are stored in the galley, and the turn buttons are visible to the observer, leading to a poor aesthetic appearance of the cart. There are also issues with ergonomics in having the turn button outside the doors. Alternatively, the turn buttons can be located on the inside of the bay doors, but this also leads to a resultant increase in the depth of a galley, and an increase in the work deck height. There are also potential cold bridge issues through the doors themselves, i.e., thermal losses resulting from conduction via the turn buttons. In this case, the doors are not normally used for retention (with the possible exception of cart kick-up loads), although additional door latching is required to secure the doors themselves.
To release the carts, both turn buttons need to be stowed which requires the use of both hands or a repeated single action, and there is no simultaneous “close-lock” operation available with this design in an emergency.
While engaged with the work deck beam, the turn buttons must withstand the twisting force imposed on their rear face by forward momentum of fully loaded carts under simulated emergency conditions. The beam is usually manufactured from aluminum, is quite heavy, and can form yet another potential cold bridge within the chilled cart compartment. The present invention is designed to overcome these disadvantages.
In addition, current turn buttons only perform their primary function of retention, and do not contribute to the galley door sealing capabilities. It would be beneficial to provide adequate chilled air leak sealing in order to meet the requirements of refrigerated galley testing and to prevent condensation. Unfortunately, the door seal is not allowed to “sweep” the floor which causes rapid wear.